ORGANIC EVOLUTION — THE FACTORS 133 



changes similax to the acquired changes in the 

 parent. 



This could only be determined by a further inquiry 

 as to whether such clear and indubitable cases of repro- 

 duction by the offspring of the acquired variations of 

 the parent, as the above, are common in nature. If it 

 were found that they commonly occur, then the case for 

 the transmission of acquired traits would be established 

 beyond cavil, and we should have either to accept one 

 of the current theories as to the way acquired varia- 

 tions are transmitted, or else to seek data whereon to 

 found a theory which would present a greater appear- 

 ance of probability than any of those yet formulated. 



As a matter of fact, however, the phenomena of nature 

 have already been ransacked for such clear cases of 

 transmission, or apparent transmission, as the above, 

 with the result that as regards the evolution of plants 

 it is now admitted on all hands that the transmission of 

 acquired variations can have played no part ; as regards 

 the higher animals alone is it generally claimed that 

 such transmission has been important as a factor in 

 evolution. Mr. Spencer says — 



" See, then, how the case stands. Natural Selection, 

 or survival of the fittest, is almost exclusively operative 

 throughout the vegetal world, and throughout the 

 lower animal world, characterized by relative passivity. 

 But with the ascent to higher types of animals, its 

 effects are in increasing degrees involved with those 

 produced by inheritance of acquired characters ; until, 

 in animals of complex structures, inheritance of acquired 

 characters becomes an important, if not the chief, cause 

 of evolution" (p. 45). 



With the first part of this statement we may well 

 agree, but there are strong grounds for demurring to 



